1. Field of the Invention:
The invention relates to fuel tanks having reserve compartments therein and systems for delivering fuel from such fuel tanks.
2. Description of the Prior Art:
Reserve fuel tanks are frequently utilized on motor vehicles. Reserve tanks are often desirable because conventional fuel gauges for indicating the amount of remaining fuel in a fuel supply system are frequently inaccurate. Further, the fuel level indication of such fuel gauges becomes quite meaningless if the vehicle is operated on a slope, because fuel collects in one corner of the gas tank, altering the level of fuel in the fuel tank with respect to the bottom of the fuel tank. This alters the level of a float, which floats on the surface of the fuel to control a sending unit which, in turn, activates the fuel gauges.
Auxiliary tanks connected to a selector valve which is connected to the engine fuel pump may provide one solution to the foregoing problem. Typically the selector valve is a solenoid-activated valve which is controlled from the dashboard of the vehicle. When one tank runs out of fuel, the driver flips a switch on the dashboard which switches the selector valve over to an auxiliary tank. At that point, the driver knows exactly how much fuel remains if the auxiliary tank is full at that point.
Auxiliary tanks have several problems. The cost of auxiliary fuel tanks is high. Usually, several fuel tanks need to be filled separately, which may be inconvenient, especially if such fuel tanks are located on opposite sides of a vehicle. Finding space for additional tanks within a particular vehicle is frequently difficult.
Motorcycles and certain small vehicles which use gravity flow fuel systems instead of fuel pumps have incorporated selector valve switches which select one of two different fuel lines which extend to different levels within such fuel tanks. This creates, in effect, a reserve supply of fuel between the levels of the higher extending and lower extending fuel lines. However, such fuel tanks provide no protection against the problem of fuel building up in a corner of the fuel tank when the vehicle is operated on a slope, so that the level of fuel in the tank falls below the level of the fuel line.
The state of the art with respect to vehicular fuel tanks is generally shown by the following U.S. Pat. Nos.: 3,949,720; 3,884,255; 3,802,596; 3,964,755; 3,968,896; 3,784,050; 4,000,727; and 3,912,107.